Surround sound is becoming widely used. Thus, the demand for convenient and cost effective recording of multi-channel surround sound is increasing. In the professional music recording domain, for example for recording of classical concerts, various techniques are being used for surround recording. When the goal is to capture the “natural spatial aspect” of a performance or concert, usually one microphone is used for each channel of the multi-channel surround audio signal. The main recording, obtained from a microphone associated with each surround channel, is often modified by using additional microphone signals, denoted spot or support microphones.
The currently used surround recording techniques are for various reasons not suitable for many applications, for example due to a requirement of small size of the microphone configuration and due to cost reasons. The Soundfield microphone manufactured by SoundField Ltd, UK, based on four nearly coincident microphones, fulfills the requirement of being relatively small. But it is a rather high-end microphone not suitable for low cost applications.
Many devices in the professional, semi-professional, and consumer domain are based on a capability to record and store a two-channel stereo signal. For example video cameras often provide only up to two audio channels which can be recorded. Some cameras provide up to four channels, but often at lower quality. Thus, even if a cost effective surround microphone would be available, it could often not be conveniently used due to the lack of devices to record and store surround audio signals.